Polysilane compounds were reported to be insoluble in solvents in (The Journal of American Chemical Society, 125, pp. 2291 (1924)). Thereafter, it was reported that polysilanes are soluble in solvents and films can be made of them (The Journal of American Ceramic Society, 61, pp. 504 (1978)). Since then, the public attention has been focussed on polysilane compounds. Further, as for polysilane compounds, it was reported that they can be dissociated with ultraviolet rays, and research was made on utilization of them in resists (Japanese Unexamined Patent Publications Sho.60(1985)-98431 and Sho.60(1985)-119550 ). Further, it was reported that polysilane compounds have photosemiconductor characteristics in which carriers are mobile due to .sigma.-bonds of their principal chains (Physical Review B, 35, pp. 2818 (1987)). And these polysilane compounds have been expected to be usable also in electrophotographic photosensitive members. However, in order that polysilane compounds be applicable in electronic materials, those polysilane compounds are required to be soluble in solvents and capable of providing films which are free of minute defects and excel in homogeneity. As for the electronic materials, any minute defect is not allowed and because of this, polysilane compounds to be used in the preparation of such electronic materials are required to be high quality polysilane compounds, which can be structurally defined also with respect to substituents and do not cause any abnormality upon film formation. There various reports have been made for synthesis of polysilane compounds. Those polysilane compounds reported are still problematic in using them in electronic materials. There are reported low-molecular weight polysilane compounds in which all the Si radicals being substituted by organic groups (The Journal of American Chemical Society, 94, (11), pp. 3806 (1972) and Japanese Patent Publication Sho. 63(1988)-38033). Those described in the former literature are of the structure in which the end group of dimethylsilane being substituted by a methyl group. Those described in the latter literature are of the structure in which the end group of dimethylsilane being substituted by an alcoxy group. Any of them is 2 to 6 in polymerization degree and does not exhibit characteristics as the polymer. Particularly in this respect, any of them does not have an ability of forming a film as it is and is not industrially applicable. High-molecular weight polysilane compounds of the structure in which all the Si radicals being substituted by organic groups have been recently reported (Nikkei New Material, pp. 46, Aug. 15 of 1988 ). These compounds are synthesized through specific intermediates to cause reduction in their yield and it is difficult to mass-produce them on the industrial scale.
In addition, methods of synthesizing polysilane compounds are reported (The Journal of Organometallic Chemistry, pp. 198 C27 (1980) and The Journal of Polymer Science, Polymer Chemistry Edition vol. 22, pp. 159-170 (1984))). However, any of these synthetic methods is directed only to condensation reaction of the polysilane principal chain but does not touch upon the end groups. And, in any of these synthetic methods, unreacted chlorine radicals and by-products due to side reactions are caused and it is difficult to stably obtain polysilane compounds as desired.
Use of polysilane compounds as a photoconductive material is reported (U.S. Pat. No. 4,618,551, U.S. Pat. No. 4,772,525 and Japanese Unexamined Patent Publication Sho. 62(1987)-269964). However, in any of these cases, occurrence of undesirable negative effects due to unreacted chlorine radicals and by-products caused by side reactions are considered.
Particularly, in U.S. Pat. No. 4,618,551, polysilane compounds are used in electrophotographic photosensitive members and an extremely high voltage of 1000 V is applied upon use of those photosensitive members, although a voltage of 500 to 800 V is applied in an ordinary electrophotographic copying machine. It is considered that this is done in order to prevent occurrence of spotted abnormal phenomena on images reproduced since defects due to the structural defects of the polysilane compound will cause in the electrophotographic photosensitive member at an ordinary potential. In Japanese Unexamined Patent Publication Sho. 62(1987)-269964, it is described that electrophotographic photosensitive members are prepared by using polysilane compounds and a photosensitivity is observed for each of them. However, none of those electrophotographic photosensitive members is sufficient in photosensitivity and is inferior to the known selenium photosensitive member or the known organic photosensitive member in any respect.
As above described, there are a number of unsolved problems for any of the known polysilane compounds to be utilized in the electronic materials. Thus, any polysilane compound which can be desirably used for industrial purposes has not yet been realized.